The target list also shows NASA’s thoughts on how it can get informative data as quickly as possible. We’ll give a little background on each of the goals below.
WASP-96 b: One of Webb’s most exciting features is its ability to analyze the composition of exoplanet atmospheres. When a planet passes between its host star and Earth, some of the star’s light will pass through its atmosphere, allowing materials in the atmosphere to absorb specific wavelengths of the star’s light. This signal is tiny since only a small fraction of the star’s light will pass through the atmosphere, so it will usually take months of observations to get a good signal.
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WASP-96 b allows us to get a good signal much faster, as it is a planet made mostly of atmosphere. While it is about half the mass of Jupiter, it is naturally larger, indicating that it is composed mostly of gas. It also has an orbital period of just 3.4 days, which means we can image its atmosphere twice a week. NASA will show the infrared spectrum of light that has passed through the atmosphere and will no doubt highlight the spectral signatures of molecules in the planet’s atmosphere.
The Carina Nebula: This will probably be a “show-only” image. The Carina Nebula is a huge cloud of gas illuminated by the massive stars forming within it. It’s home to the brightest star we’ve spotted in our Galaxy, as well as Eta Carinae, my favorite candidate for “most likely to go supernova.” The star came so close to being destroyed in a massive explosion about 175 years ago that it formed a nebula within the Carina Nebula.
This image will look impressive. And there is potentially interesting science to be done here. Webb should have the ability to work out smaller-scale structures within the nebula and perhaps even determine the flow of gas in certain regions based on changes in the spectrum caused by red and blue shift. Finally, Webb may be able to detect some interesting molecules in the cooler regions of the nebula. But I suspect it will take some time to get past the awe-inspiring aspects of the picture before anyone pays attention to the science.
